1. Field of the Invention
The present invention relates to a copying method and a copying apparatus for obtaining collated duplex copies from duplex documents which is particularly advantageous for obtaining two or more copies from a plurality of duplex documents.
2. Description of the Prior Art
U.S. Pat. No. 4,099,150 discloses a copying apparatus capable of obtaining duplex copies collated in page sequence from a plurality of duplex documents. In this copying apparatus, when obtaining collated duplex copies from a plurality of duplex documents, after copying one side of all duplex original documents, the other side is copied.
The original feeder of this copying apparatus comprises two original hoppers, and the duplex documents are first put on a first original hopper. When copying one side of the duplex documents, the duplex documents are moved from the first original hopper to a second original hopper, and are supplied from the second original hopper into an exposure region by circulation. When copying of one side of duplex documents is over, the duplex documents are moved from the second original hopper into the first original hopper in order to be turned upside down, and are further moved from the first original hopper into the second original hopper. In this way, the duplex documents turned upside down are supplied again into the exposure region by circulation, and the other side is copied.
In such copying apparatus, aside from the circulation of the documents for copying action, the movement of the documents from the first original hopper into the second original hopper upon start of copying, and the movement for inverting the face-back relation after copying of one side are needed, and requires an enormous time until copying of a plurality of duplex documents is.